| Popis: |
During an ultrastructurc study of cells of both parental field material and cultured sporelings of thc marine bro\v11 alga Lecrtbesicr diffo?r//is (Chordarialcs) it was notcd that chloroplasts of tlic ficld thalli typical of those previousl>rcportcd in otlicr brown algae. Hoivercr, at least two featurcs of chloroplast structure \verc unique in many cclls of tlic culturcd sporclings: constant thrcethylaltoid type banding \vithout variation in tlic number of discs and thc formation of extra bands bctwccn the regular oncs in an intcrmcdiatc region, resulting in a staclc of as many as 40 to 60 long, loosely-associated discs. Introductioli There are relatively few records of electron microscope studies of chloroplasts in the brown algae and only 16 genera are represented. Most u~oriters have observed field material and are now in general agreement regarding the chloroplast ultrastructure (Gibbs, 1962a, b; Greenwood, 1964; Bouclt, 1965). 'The whole length of the chloroplast is traversed by bands consisting of three thylaltoids or discs which are not usually closely appressed. The bands arc separated by uniform spaces and, occa~i~nally, discs may appear to leave one band and join another. In addition, a peripheral band or 'girdle' follows the contour of the chloroplast underneath the chloroplast membrane. To date. there have been no reports of grana similar to those in the chloroplasts of higller plants and some of the green algae (Kirk and Tilney-Bassctt, 1967). During a study of the life cycle of Lenthesia diffo~71Gs (L.) Aresch. both field and cultured material were fixed and embedded for electron microscope observation. Since this marine alga is a member of the order Chordariales in the class Phaeophyceae (Scagel, 1957) it was expected that the chloroplast ultrastructure would be typical of the br0a.n algae alreadv studied. This was found to be so for the parental field material. on-ever; extensive thylalioid stacliillg not previously reported in the brown algae was noted in cells of the culturcd sporeiings. The present paper serves to record this unique feature of chloroplast structure. Materials and Metl~ocla |
